The principal objectives of this project are part of the on-going effort identifying antiplaque and anticaries agents suitable for short-term clinical investigation, as well as, to develop methods for assessing the clinical potential for these agents; e.g., its staining properties. Octenidine has been identified by our laboratory as an agent which restricts dental plaque and caries in rats. Used as a rinse twice daily in a 1% solution, the results compared favorably to chlorhexidine (Annual Report 1980-1981). In this study an oral rinse of 1% octenidine was found to provide caries restriction when used only once daily. Our efforts also have been directed toward developing a rat staining model as a means of improving the drug screening process.